This invention generally relates to the art of electrical connectors and, particularly, to a filtered electrical connector.
Generally, an electrical connector includes some form of dielectric housing which mounts a plurality of conductive terminals for making electrical connection with the terminals of a complementary mating connector or other connecting device or to the circuit traces on a printed circuit board, flat flexible cable or the like. Many connectors are shielded or filtered to protect against interference with the electrical signals carried by the terminals.
For instance, a shielded connector may have external shields to protect against ingress or egress of electromagnetic interference (EMI) or radio frequency interference (RFI) at the connector interface. A filtered connector may have some form of internal filtering element or elements to prevent internal interference or xe2x80x9ccross talkxe2x80x9d between the terminals of the connector.
One form of filtered connector includes a plurality of terminal pins which extend through holes in a filtering block, such as a block fabricated of ferrite material. The ferrite block typically is held onto the terminal pins by a thin plastic sheet, such as polyester film. The plastic sheet has holes press-fit over the terminal pins, whereby the plastic sheet performs a dual function of holding the ferrite block on the terminal pins as well as providing a spacing aligner for the pins.
One of the problems in using ferrite filtering blocks of the character described above is that the blocks tend to push the plastic aligner sheet off of the terminal pins. In addition, the pin holes in the ferrite block are larger than the pins, themselves, because it is difficult to maintain sufficiently precise tolerances in ferrite or similar materials. Consequently, the ferrite block tends to impact against the pins as well as rub against the pins, resulting in abrasion of the highly conductive plating on the pins. Furthermore, the ferrite block can force the plastic sheet away from the pins. Nor will a press-fit polyester film sufficiently hold the ferrite block on the filtered connector without some additional encapsulation. The present invention is directed to solving these various problems by a unique mounting of filtering blocks, such as of ferrite material, onto connectors about portions of terminals such as terminal pins.
An object, therefore, of the invention is to provide a new and improved filtered electrical connector of the character described.
In the exemplary embodiment of the invention, the connector includes a dielectric housing having an array of terminal-receiving passages and at least one mounting post projecting from the housing outside the array of passages. A plurality of terminals are received in the passages and include a plurality of pin portions projecting from the housing in the same direction as the mounting post. A filter block is fitted over the pin portions of the terminals. The filter block includes a plurality of pin-receiving holes through which the pin portions of the terminals extend and a mounting hole closely fit about the mounting post projecting from the housing. In the preferred embodiment, the filter block comprises a ferrite block.
According to one aspect of the invention, a distal end of the mounting post is expanded over the filter block to hold the block on the mounting post. The mounting post also includes an abutment portion projecting from at least one side thereof and against which the filter block abuts when positioned over the mounting post. In the preferred embodiment, a plurality of the mounting posts project from the housing and into a corresponding plurality of mounting holes in the filter block. The terminal-receiving passages and respective pin portions are arranged in a generally linear array, with one of the mounting posts located at each opposite end of the linear array.
According to another aspect of the invention, an alignment sheet is press-fit onto the mounting post over the filter block and includes a plurality of pin-receiving holes closely fit about the pin portions of the terminals. A distal end of each mounting post is expanded over the alignment sheet to hold the sheet and the filter block on the mounting posts.
Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings.